Microneedle electrodes for collecting bioelectrical signals: from a materials science perspective
image: Microneedle electrodes can penetrate beneath the skin, allowing for more accurate bioelectrical signal acquisition (such as EEG, ECG, and EMG) from outside the body. Research into their materials has accelerated the development and commercialization of wearable devices, myoelectric exoskeletons, brain-machine interfaces, and brain-controlled games.
Credit: Nano research, Tsinghua University Press
Bioelectrical signals can reflect the physiological state of organs or tissues and serve as key indicators for clinical diagnostics, health assessments, and physiological behavior analysis. For example, electrocardiograms(ECGs) are used for heart disease screening, remote monitoring, and wearable devices; electromyograms(EMGs) aid in neurorehabilitation, prosthetic control, and exoskeletons; electroencephalograms(EEGs) support epilepsy diagnosis, sleep monitoring, brain-computer interfaces, and brain-controlled gaming. The in-depth study and application of these bioelectrical signals fundamentally depend on effective and precise signal acquisition. Currently, electrodes used for bioelectrical signal collection are mainly classified into non-invasive and invasive electrodes. While invasive electrodes offer high accuracy, they involve complex implantation procedures and pose long-term stability risks within the body. On the other hand, non-invasive electrodes are convenient but often lack sufficient precision. Microneedle electrodes fall between these two categories and are considered minimally invasive electrodes. These needle-like structures are specifically designed to penetrate the stratum corneum and reach the subcutaneous tissue. By bypassing the high impedance introduced by the stratum corneum, microneedle electrodes significantly enhance the quality and accuracy of bioelectrical signal recording.
A team of material scientists led by Ting-Kai Zhao from Northwestern Polytechnical University in Xi’an, China recently comprehensively reviewed microneedle electrodes for bioelectrical signal acquisition, covering electrode materials, fabrication methods, performance evaluation, and applications. Their study particularly emphasizes the development of materials used for microneedle electrode fabrication, discusses challenges related to material selection and performance testing, and provides insights into future trends in this field.
The team published their review in Nano research on April 30, 2025.
Microneedle Electrodes Empower the Next Generation of Bioelectrical Signal Acquisition
Against the backdrop of rapid advancements in wearable health monitoring and neuroscience research, a recent review highlights the tremendous potential of microneedle electrodes in bioelectrical signal acquisition. The paper, titled Microneedle electrodes for collecting bioelectrical signals: from a materials science perspective, systematically summarizes the latest developments in microneedle electrodes from a materials science perspective, providing direction for future innovative research.
A Precise, Efficient, and Non-invasive Bioelectrical Signal Acquisition Technology
Traditional bioelectrical signal acquisition methods often rely on surface electrodes, but their signal quality is affected by skin contact impedance, and prolonged use may cause skin irritation. In contrast, microneedle electrodes, with their minimally invasive penetration of the skin, significantly reduce contact impedance, enhance signal quality, and offer greater wearing comfort. This technology shows broad application prospects in wearable health monitoring, brain-computer interfaces, and ECG/EEG signal detection.
Material Innovation Driving the Development of Microneedle Electrodes
This review explores the application of metals, polymers, carbon-based, and composite materials in microneedle electrodes from a materials science perspective. It emphasizes that material selection directly determines the mechanical strength, biocompatibility, and electrochemical performance of microneedles. For instance, the introduction of conductive polymers and nanomaterials has significantly improved the flexibility, conductivity, and long-term stability of microneedle electrodes.
Aligning with the Trends of Wearable and Personalized Healthcare
With the widespread adoption of wearable medical devices and the growing demand for personalized healthcare, microneedle electrode research has become a global focus. This paper not only summarizes current research but also looks ahead to future technological trends, including the integration of smart microneedle systems, the application of 3D printing in manufacturing, and the combination of biosensors for multimodal health monitoring.
The publication of this paper provides essential theoretical support for the further development of microneedle electrode technology and serves as a comprehensive reference for researchers in related fields. If you are conducting research on bioelectrical signal acquisition or materials science, we welcome you to cite this paper and join us in advancing this cutting-edge technology!
The research team expects the review to rapid development of microneedle electrodes with bioelectrical signal acquisition in wearable health monitoring and neuroscience research. “Microneedle electrodes for bioelectrical signal acquisition are expected to become more diverse and practical in the coming years. In the same part of the body, the human and machine can interact with different signals… in many different ways,” said Ting-Kai Zhao.
Other contributors include Xianghong Li from the School of Materials Science and Engineering at Northwestern Polytechnical University in Xi’an, China.
This work was supported by by the National Natural Science Foundation of China (Nos. 51672221, 51872231) and the Key Industrial Chain Project of Shaanxi Province (No. 2018ZDCXL-GY-08-07).
About the Authors
Xiang-Hong Li is a 2022 PhD student in School of Materials Science & Engineering at Northwestern Polytechnical University, Xi’an China. His research focuses on the fundamental applications of carbon nanotubes, graphene, novel 2D materials, and carbon-based composites. In particular, he is good at structural design and process optimization for enhancing the performance of biosensors, contributing to advancements in precision medicine and wearable health monitoring. As the first author, he has published two papers in Ceramics International and Nano Research.
Dr. Ting-Kai Zhao is currently working as a full professor in School of Materials Science & Engineering of Northwestern Polytechnical University (NPU), Xi’an China, IAAM fellow and a director of NPU-NCP Joint International Research Center on Advanced Nanomaterials & Defects Engineering, and a director of Shaanxi Engineering Laboratory for Graphene New Carbon Materials & Applications. His research mainly focused on the simulation, synthesis, structure and performance of carbon nanotubes, graphene, borophene, expanded graphite, 2D nanomaterials, MXene, MBene and their composites, and the applications in energy conversion (supercapacitor, Li-ion batteries, solar cell), EMI Shielding & EMW absorption, smart device & biosensors(microneedle electrodes, photosensitizer). Prof. Zhao has published 10 books, 19 Chinese Invention patents and more than 200 academic articles on SCI journals, and also obtained more than 20 research funds & 30 Awards and Honors such as IAAM Scientist Award, the first prize of Shaanxi Science and Technology Awards in 2013 etc, and his research achievements have been reported on《China Science Daily》5 times. From 2019, he has organized GANDE & GNN international conferences as general chair in every year, and also been elected as a executive director of Xi’an Society of Nano science & Technology. For more information, please pay attention to his research homepage https://teacher.nwpu.edu.cn/en/zhaotingkai.html .
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.